An election is like flipping a coin that lands on a side with relatively substantial weight of public support (quirks of electoral systems mean it's not guaranteed to be the most popular or least unpopular side, but unless it's blatantly rigged, substantial public support will be there). A revolution is flipping a coin that lands on the side most effectively able to concentrate violence. Sometimes that's achieved by overwhelming public support, but if your "revolution" is a military coup, it doesn't need many people to be on side at all.